Rotary pump.



I. ROBERTS & W. SHAW.

ROTARY PUMP. APPLICATION FILED JUNE 24, 1915.

Patented July 2, 1918.

WHOM/EV UNITED sTATEs PATENT OFFICE.

ISAAC ROBERTS AND WILLIAM SHAW, OF BROOKLYN, NEW YORK, ASSIGNORS TO SAID ISAAC ROBERTS.

ROTARY PUMP.

tain new and useful Improvements in R0- tary Pumps, ofwhich the followingis a specification.

This invention relates to what are generally known as rotary pumps, with more particular reference to pumps employed for the compression or exhaustion of air,

although itwill be apparent that a rotarypump embodying our invention may be employed for many other, purposes.

We have still more particularly in mind certain improvements in the general construction of the amp shown and described in the patent to rowell No. 848,446, granted March 26, 1907, and t e present invention has for its more especial ob ects, first, a constructional simplification of the Crowell device; second, the provision of means for regulating the amount of power utilized in driving the device proportionately to the volume of fluid wh1ch is intended to be forced therethrough-and thus being able to economize in power when comparatively slight pressure or compression is desired; third, to eliminate one of the usual hearings in the pump cylinder, and thereby minimize wear and the avenues of possible leakage, and, fourth in general to provide a construction which while exceedingly simple will prove durable and dependable in connection with the very largest as well as the very smallest sizes of pumps.

Our invention will be more readily understood by reference to the accompanying drawings, forming a part of this specification, in which Flgure 1 is a central sectional elevationof a rotary pump embodying our invention;

Fig. 2 1s a transverse vertical section taken substantially on the line II-II of Fig. 1;

Fig. 3 is an elevation of the interior face of one of the removable cylinder heads or ends, hereinafter described;

Fig. '4 is an end elevation of Fig. 1, with the driving pulley removed; a Fig. 5 is a fragmentary view similar to "Fig. 3, with the'regulating valve in a different position of adjustment, and,

Specification of Letters Patent.

Application filed ..'une 24, 1915. Serial No. 86,062.

Fig. 6 is a detail view of the regulating valve, as hereinafter described.

Referring now to the drawin s in detail numeral 11 designates a prefera 1y integral cylinder, having one open end and for the purpose of this description shown as includmg a suitable base 12 which may be screwed or otherwise secured to any desired support. This member, which is preferably a finished casting, also includes a transversely disposed enlarged vide cham ers l3 and 14, which are open to the cylindrical pump chamber 15, these chambers also having ports 16 and 17, respectively, one thereof leading through any suitable connecting means to a source of air or other fluid supply and the other leading through suitable connecting means to the compression chamber or to such other ultimate destination as is intended for the fluid. Of course, if the device is to be operated as a vacuum pump, one of these ports will lead to the chamber from which it is desired to exhaust the air, and the otherwill lead to atmosphere.

The cylinder head or end 18, which closes and seals the open end of the pump cylinder, is designed to be secured in place by means of screws 19, and preferably forms an integral part of the member which includes the shaft bearin s 20 and 21. This member also includes a ll-shaped portion 22 to permit of the mountin of a driving pulley 23 between the shaft earings aforesaid. It Wlll be noted that this entire member is supported by the cylinder 11. I

The driving shaft 24 is mounted eccentrically with respect to the cylindrical pump chamber, and carries at its end, within said chamber, the substantially solid drum or c linder 25. This drum 25 is of substantia 1y the same width as that of the pump chamber 15, fittin within said chamber as snugly as is practicable, considering that the drum. 'must rotate very rapidly within said chamber and the friction must not be excessively great. The diameter of the drum 25 is somewhat less than the diameter of the chamber 15, and the former is so located in the latter that. the top faces thereof are substantially ortion on its upper side to pro- The drum 25 is provided with a plurality-preferably three-of radially disposed longitudinal slots, located e uidistantly from each other. Loosely ttlng within each of the three slots is a free p1s- .ton 26, of approximately the same dimensions as the slot, having a limited, sl1d1ng radial movement therein and rotating with the drum or cylinder 25. At the bottom of each slot is provided a small pocket or recess for the reception of a compression spring 27, the yielding forces of which constantly tend to impel the piston in a direction away from the center of the drum 25. It will be apparent, therefore, that as this drum is rotated within the chamber 15, each 'piston will be yieldin ly held against the peripheral wall of sai chamber, moving in and out .of its retaining slot as it approaches 'or recedes from the position where said drum is in contact with said wall.

We are aware that no broadly new principles are involved in the construction of rotary pump described above. However, it

has been found, particularly in connection with pumps of larger sizes, that it is sometimes necessary to reduce either the volume of the fluid being forced through the pump or the pressure to which the same is :sub-

jected on the discharge .side of the pump.

w Obviously, this may be accomplished by reducing the velocity at which the pump is driven, but -with rota pumps of this-t e a reduction of speed as been found to e undesirable and not economical. Furthermore, any ordinary choking of the supply for the purpose .set forthv still renders necessary the utilization of substantially the same amount of driving power, and one of the features of the present invention grows out of our effort to conserve power when the capacity of the pump has'been reduced.

For this purpose, we provide a bore 28 in the cylinder head or end 18, and cut grooves 'or channels 29 and 30 in. the interior face of said head, leadmg from the spaces on oppo-.

site sides ,ofthe drum 25-tothe bore 28.

Within this bore we mount the rotary valve 31, the inner end of which abuts against the face of the drum 25 and which may be rotated to open and close the ends of the chem,

'nels'29 and 30 at the bore 28. This valve is preferably provided with a head32, on. the exterior face of the cylinder head or end 18, whereby said valve may be operated by shown and described.

the device is designed to be worked to its full capacity.

When it is desired to reduce'this capacity, the valve 31 is rotated to open the closed end of the groove 29, and thus provide (an open passage between the spaces referred to on opposite" sides of the drum. The extent to whichthe valve is opened may obviously be regulated from an exceedingly small opening to that of substantially full extent, as illustrated in Fig. 3.

As is doubtless apparent from the drawings, if not otherwise well known, if the. drum 25 is rotated in the direction of the arrow, the chamber or space above the piston which has just cleared the chamber 13, will be constantly increasing in size. Therefore, air or other fluid will be drawn in through the port 16 until this space reaches its maximum size, which happens just after the next succeeding piston has cleared the opening from the chamber 13. From this I point on, there is'little change in the. size of the containing chamber until the fore-v most piston reaches the opening to the discharge chamber 14, whereupon the space within the cylinder is decreased in size to drive the air or other fluid from the port 17.

It will be seen that if the valve 31 is rotated'to open the'end of the groove or channel 29, at least a part of the fluid in the'discharge space will be directed back into the intake space, the volume of this shunted fluid being capable of regulation by means of the valve 31. Therefore, the amount of power required to drive the chamber may be materially .reduced by using a portion of the compressed fluid to assist in the driving-operation-imd this without reducing the velocity of the moving parts.

is a matterpf no inconsiderable importance. In additlon to the general simplicity of Inthe larger sizes of blowers and compressors this construction of the device-shown and described, attention is again called to the fact that the driving shaft is mounted in bearmgs which are carried by one only of the cyllnder heads, the other head being therethe parts subject to the greatest wear, it will be apparent that I have reduced by one-half the sources of ultimate excessive leakage'andtherefore the number of parts necessary to be replaced on this account.

.fore imperforate, and as these bearings are Many modifications of minbr details ofv our improved, rotary pumps will doubtless I I I and desire ti; secure byl- Letters P en I "1. Ina rotary pump, inbombinatioh, 8

readily suggestthemselves to those skilled .in the art to which. it appertains, and we piston carrying drum, a cylinder providing a pump chamber ,in which said drum is eccentrically mounted, cylinder heads one of which is provided with intersecting grooves leading from opposite sides of the pump chamber, and a valve at the intersection of said grooves adapted to regulate the volume of fluid that can pass through said grooves from one side of the pump chamber to the other.

2. In a rotary pump, in combination, a piston carrying drum, a cylinder providing a pump chamber in which said drum is eccentrically mounted, cylinder heads one of which is an integral part of said cylinder,. ,the other being detachable and provlded with intersecting grooves leading from opposite sides of the pump chamber, and a valve at the intersection of sad grooves adapted to regulate the volume of fluid that can pass through said grooves from one side ing grooves leading from opposite sides of the pump chamber, and a valve at the intersection of said grooves radapted to regulate the volume of fluid that can pass through said grooves from one side of the pump chamber to the other.

4. In a rotary pump, in combination, a piston carrying drum, a cylinder-providing a pump chamber open at one end in which the drum is ecoentrically mounted, a detachable head adapted to close the open end of the cylinder, means carried by said head for rotatively supporting the driving shaft for said drum, the inner face of said head being provided with intersecting grooves leading from opposite sides of the pump chamber, and a valve at the intersection of said grooves adapted to regulate the volume of fluid that can pass through said grooves from one side of the pump chamber to the other.

In testimony of the foregoing, we have hereunto set our hands in the presence of two witnesses.

Isaac ROBERTS. WILLIAM SHAW.

Witnesses: v SARA Gnoss, HAROLD R. I CoNwAr. 

